Technical indicators Basis weight:19.0 +/- 1.5g/m2 Dry tensile strength (MD):≥0.50kN/m Wet tensile strength (MD):≥0.25kN/m Dry tensile strength (CD):≥0.20 kN/m Air permeability:≥1900L/m2.s Appearance:Uniform Normal specifications:180mm and 200mm roll paper Purpose:Used for the close to face lay of anti virus mask